1. Field of the Invention
This invention relates to a high frequency discharge ignition device to be used mainly in an internal combustion engine.
2. Description of the Related Art
In recent years, problems relating to environmental conservation and fuel depletion have been raised, and responding to these problems also represents an urgent task in the automobile industry. As an example of a response thereto, there exists a method in which fuel consumption is improved through engine downsizing using a supercharger. However, if a supercharger is used, pressure in an engine combustion chamber becomes extremely high even in a state where combustion is not occurring, making it difficult to generate a spark discharge for initiating combustion. For this reason, a spark plug gap is narrowed. However, if the spark plug gap is narrowed, loss of thermal energy increases due to the anti-inflammatory effect, that is, the effect by which energy that allows a spark having just been generated to grow is depleted by a low temperature electrode part, which results in the occurrence of a decrease in startability or a decrease in combustibility.
As one solution to this problem, a method has been considered in which thermal energy that exceeds the energy depleted by the anti-inflammatory effect is provided by a spark discharge. For example, Japanese Patent Application Laid-open No. 2015-078666 describes a high frequency discharge ignition device that makes it possible for a high-energy spark discharge to be formed by supplying, to a spark plug, high frequency energy having a high voltage and acquired by coupling high frequency energy boosted by a boosting circuit with a spark discharge generated by a conventional ignition coil.